The next few weeks are crucial for both Democrats and Republicans, as the presidential candidates try to earn enough delegates to secure their parties' nominations.

On the Democratic side, New York Sen. Hillary Clinton could use a win between now and key March 4 contests in Texas and Ohio. The Wisconsin primary on Feb. 19 offers Clinton the chance to disrupt Illinois Sen. Barack Obama's winning streak. Since Super Tuesday, Obama has won eight contests in a row — most recently, in Maryland, Virginia and the District of Columbia.

For the Republicans, Wisconsin will offer Arizona Sen. John McCain the chance to pick up more delegates. The state's demographic make-up — overwhelmingly white, with a large number of Democratic, independent and progressive voters — favors McCain: These groups have been the bedrock of much of his support during the primaries.

Look for campaign stops and television ads in Wisconsin in the coming days. Both Obama and Clinton (through her daughter, Chelsea) have already begun campaigning in the state.

The Democrats

Candidates: New York Sen. Hillary Clinton; Illinois Sen. Barack Obama

What's at Stake: Clinton and Obama are battling for the 74 delegates at stake in Wisconsin — and for the momentum that victory there would bring them going into the March 4 nominating contests in Texas, Ohio, Rhode Island and Vermont.

Wisconsin's demographics would seem to favor Clinton, since she has done well with white, working-class voters in many primaries this year (Wisconsin's population is 87.5 percent white).

But the state boasts a history of progressive politics that could benefit Obama. The 1960 primary, for instance, was crucial in helping John F. Kennedy win the Democratic nomination over rival and fellow senator Hubert Humphrey.

In 2004, Howard Dean's failure to win the Wisconsin primary essentially ended the former Vermont governor's presidential campaign. Massachusetts Sen. John Kerry carried the state that year and went on to win the nomination.

If Republican voters decide that their party's nomination is already locked up, they — and independent voters — could decide to participate in the Democratic contest; Wisconsin allows voters to participate in either party's primaries.

What's at Stake: McCain has far more delegates than his rivals and is still perceived as the party's front-runner, but Huckabee has managed to continue winning — most recently, in Louisiana and Kansas. On Super Tuesday, he did especially well in the South, winning Alabama, Georgia, Tennessee, West Virginia and Arkansas.

While Wisconsin does have a segment of evangelical voters — a group that overwhelmingly helped Huckabee win the Iowa caucuses — they have not been very active in the state's past primaries.